:root {
  --bg: #faf9f5;
  --bg-alt: #f2f1ec;
  --ink: #0d1a2b;
  --ink-soft: #54617a;
  --brand: #1677ff;
  --brand-ink: #0b53c0;
  --dark: #0a0e1a;
  --line: #e6e3da;
  --ok: #12b886;
  --warn: #ffb020;
  --font-sans: "IBM Plex Sans", "IBM Plex Sans SC", system-ui, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, "IBM Plex Sans SC", "PingFang SC", monospace;
  --step-0: 1rem; --step-1: 1.25rem; --step-2: 1.6rem; --step-3: 2.2rem; --step-4: 3rem;
  --space: 1rem; --radius: 14px; --radius-lg: 18px; --maxw: 1160px;
  /* 精修增质:品牌浅底 + 卡片/浮层阴影,全站共享 */
  --brand-wash: #eaf1ff;
  --shadow-card: 0 14px 34px -18px rgba(13, 26, 43, .14);
  --shadow-float: 0 10px 24px -8px rgba(13, 26, 43, .18);
}